The current standard method (e.g., defined in X.S0042-A v1.0 by the Third Generation Partnership Project 2 (3GGP2)) allowing assignment of a mobile directory number (MDN) (e.g., homed to a mobile switching center (MSC) of a code division multiple access (CDMA) network) to a mobile served by an Internet protocol (IP) multimedia subsystem (IMS) network requires a voice call continuity (VCC) application server (AS) to support a wireless intelligent network (WIN) trigger. However, this method cannot be implemented if the VCC AS does not support a WIN termination trigger message (i.e., an Analyze Information Invoke message as specified in X.S0042-A v1.0) or if there is no VCC AS deployed in the IMS network.